We are flying the 03:20 Flight DEL-LHR.
1) How early do do the BA checkin counters open.
If you go to Manage My Booking -> Check In -> other ways to check
This will show you what time BA Counters open.
Don't know how current the answers are from the last time the questions were asked :
BA142 DEL-LHR at 3am. OLCI, early access airside and AUPs?